Ultra-low molecular weight ethylene polymers

ABSTRACT

The subject invention pertains to a non-pourable homogeneous ultra-low molecular weight ethylene polymer composition and a process for the preparation thereof Such polymer compositions have longer lamella and a greater degree of crystalline organization than corresponding higher molecular weight materials at an equivalent density.

CROSS-REFERENCE TO RELATED APPLICATIONS

This United States application claims priority from provisionalapplication Ser. No. 60/010,403 filed Jan. 22, 1996 and provisionalapplication Ser. No. 60/030,894 filed Nov. 13, 1996. This application isalso a divisional application of U.S. Ser. No. 08/784,683 now U.S. Pat.No. 6,054,544 filed on Jan. 22, 1997 issued Apr. 25, 2000.

FIELD OF THE INVENTION

The subject invention pertains to ethylene polymers having an ultra-lowmolecular weight, as evidenced by a low number average molecular weight.In particular, the subject invention pertains to ethylene polymershaving a number average molecular weight as determined by gel permeationchromatography of no more than 11,000.

BACKGROUND OF THE INVENTION

U.S. Pat. No. 3,645,992, incorporated by reference herein in itsentirety, discloses homogeneous linear ethylene olefin copolymersprepared using a soluble vanadium catalyst. Therein, homogeneouscopolymers are defined as polymers in which the comonomer is randomlydistributed within a given molecule, and in which all copolymermolecules have the same ethylene to copolymer ratio. The disclosedhomogeneous copolymers have a moderately high molecular weight. Forinstance, as set forth in the Examples, the homogeneous copolymers havea melt index, as measured in accordance with ASTM D-1238, of from lessthan 0.1 to less than 25 g/10 min.

U.S. Pat. Nos. 5,272,236 and 5,278,272, incorporated by reference hereinin their entirety, disclose substantially linear ethylene olefincopolymers prepared using a single site polymerization catalyst. Thedisclosed substantially linear copolymers are characterized as havingfrom about 0.01 to about 3 long chain branches per 1000 carbons. Unlikethe homogeneous copolymers of Elston, the disclosed substantially linearcopolymers are characterized by a molecular weight distribution(M_(w)/M_(n)) which is independent of the I₁₀/I₂, as measured inaccordance with ASTM D-1238.

Pourable ultra-low molecular weight ethylene polymers for use as oiladditives are known in the art. For instance, PCT published application93/12193 discloses ethylene/butene copolymers having a number averagemolecular weight between 1500 and 7500 prepared using abiscyclopentadienyl metalLocene catalyst. Such polymers are said toexhibit a pour point of −30° C. or less, as determined by ASTM MethodNo. D97. As set forth in the published application, polymers exhibitingsuch low pour points do not adversely affect the pour point of alubricant to which they are added.

Non-pourable ethylene polymers having a narrow molecular weightdistribution, i.e., an M_(w)/M_(n) less than 2.5, and an ultra-lowmolecular weight, as evidenced by a number average molecular weight (Mn)of no more than 11,000, have been heretofore unknown. Industry wouldfind advantage in such polymers for use in adhesive formulations, and aswax substitutes, ink modifiers, oil modifiers, viscosity modifiers,fibers, processing aids, sealants, caulks, etc.

SUMMARY OF THE INVENTION

Accordingly, the present invention further provides a non-pourablehomogeneous ultra-low molecular weight ethylene polymer which ischaracterized as having a number average molecular weight (Mn), asdetermined by gel permeation chromatography, of no more than 11,000, anda molecular weight distribution (M_(w)/M_(n)), as determined by gelpermeation chromatography, of from 1.5 to 2.5.

The present invention further provides a non-pourable homogeneousultra-low molecular weight ethylene polymer having longer lamella and agreater degree of crystalline organization than corresponding highermolecular weight materials at an equivalent density. In one instance,the present invention provides a non-pourable homogeneous ultra-lowmolecular weight semicrystalline ethylene/α-olefin interpolymer having adensity less than 0.900 g/cm³ characterized as having lamella greaterthan 40 nanometers in length when viewed using transmission electronmicroscopy.

The present invention further provides a process for preparing thenon-pourable homogeneous ultra-low molecular weight ethylene polymers ofthe invention comprising: reacting ethylene and at least oneethylenically unsaturated comonomer at a reaction temperature of atleast 80° C. in the presence of a constrained geometry catalyst to forma non-pourable homogeneous ultra-low molecular weight ethylene polymerwhich is characterized as having a number average molecular weight (Mn)of no more than 11,000, and a molecular weight distribution,M_(w)/M_(n), as determined by gel permeation chromatography, of from 1.5to 2.5.

These and other embodiments of the claimed invention are more fully setforth in the Detailed Description set forth below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1(a) is a simplified representation of features of a transmissionelectron micrograph of a homogeneous ethylene/1-octene copolymer havinga density of from 0.86 to 0.88 g/cm³ and an I₂ of 1 g/10 min.;

FIG. 1(b) is a simplified representation of features of a transmissionelectron micrograph of a homogeneous ethylene/1-octene copolymer havinga density of from 0.88 to 0.91 g/cm³ and an I₂ of 1 g/10 min.;

FIG. 1(c) is a simplified representation of features of a transmissionelectron micrograph of a homogeneous ethylene/1-octene copolymer havinga density of from 0.91 to 0.93 g/cm³ and an I₂ of 1 g/10 min.;

FIG. 1(d) is a simplified representation of features of a transmissionelectron micrograph of a homogeneous ethylene/1-octene copolymer havinga density greater than 0.95 g/cm³ and an I₂ of 1 g/10 min.;

FIG. 2(a) is a transmission electron micrograph, at a magnification of90,000 times, of an ethylene/1-octene copolymer having a density of0.855 g/cm³ and an I₂ of 0.5 g/10 min.;

FIG. 2(b) is a transmission electron micrograph, at a magnification of90,000 times, of the ultra-low molecular weight polymer of Example 1 (anethylene/1-octene copolymer having a density of 0.855 g/cm³, an Mn of4,600, and a melt viscosity at 350° F. of 350 centipoise);

FIG. 3(a) is a transmission electron micrograph, at a magnification of90,000 times, of the polymer of Comparative Example D (a substantiallylinear ethylene/1-octene copolymer having a density of 0.870 g/cm³ andan I₂ of 1 g/10 min);

FIG. 3(b) is a transmission electron micrograph, at a magnification of90,000 times, of the polymer of Comparative Example C2 (anethylene/1-octene copolymer having a density of 0.875 g/cm³ and an I₂ of246 g/10 min.);

FIG. 3(c) is a transmission electron micrograph, at a magnification of90,000 times, of the ultra-low molecular weight polymer of Example 2 (anethylene/1-octene copolymer having a density of 0.871 g/cm³, an Mn of9,100, and a melt viscosity at 350° F. of 4200 centipoise);

FIG. 3(d) is a transmission electron micrograph, at a magnification of90,000 times, of the ultra-low molecular weight polymer of Example 3 (anethylene/1-octene copolymer having a density of 0.870 g/cm³, an Mn of4,200, and a melt viscosity at 350° F. of 355 centipoise);

FIG. 4(a) is a transmission electron micrograph, at a magnification of90,000 times, of the ultra-low molecular weight polymer of Example 4 (anethylene/1-octene copolymer having a density of 0.897 g/cm³, an Mn of8,700, and a melt viscosity at 350° F. of 5200 centipoise);

FIG. 4(b) is a transmission electron micrograph, at a magnification of90,000 times, of the ultra-low molecular weight polymer of Example 17(an ethylene/1-octene copolymer having a density of 0.890 g/cm³, an Mnof 4500, and a melt viscosity at 350° F. of 350 centipoise);

FIG. 5 is a transmission electron micrograph, at a magnification of90,000 times, of a substantially linear ethylene/1-octene copolymerhaving a density of 0.915 g/cm³ and an I₂ of 1 g/10 min.;

FIG. 6(a) is a transmission electron micrograph, at a magnification of90,000 times, of the ultra-low molecular weight polymer of Example 5 (anethylene/1-octene copolymer having a density of 0.929 g/cm³, an Mn of8,900, and a melt viscosity at 350° F. of 5600 centipoise);

FIG. 6(b) is a transmission electron micrograph, at a magnification of90,000 times, of the ultra-low molecular weight polymer of Example 18(an ethylene/1-octene copolymer having a density of 0.930 g/cm³, an Mnof 4700, and a melt viscosity at 350° F. of 400 centipoise);

FIG. 7(a) is a transmission electron micrograph, at a magnification of90,000 times, of a substantially linear ethylene homopolymer having adensity of 0.960 g/cm³ and an I₂ of 1 g/10 min.;

FIG. 7(b) is a transmission electron micrograph, at a magnification of90,000 times, of the ultra-low molecular weight polymer of Example 6 (anethylene/1-octene copolymer having a density of 0.963 g/cm³, an Mn of8,000, and a melt viscosity at 350° F. of 5200 centipoise);

FIG. 7(c) is a transmission electron micrograph, at a magnification of90,000 times, of the ultra-low molecular weight polymer of Example 7 (anethylene/1-octene copolymer having a density of 0.968 g/cm³, an Mn of3,700, and a melt viscosity at 350° F. of 395 centipoise);

FIG. 8 is a transmission electron micrograph, at a magnification of90,000 times, of the ultra-low molecular weight polymer of Example 13(an ethylene/1-butene copolymer having a density of 0.868 g/cm³ and amelt viscosity at 350° F. of 5290 centipoise);

FIG. 9 is a transmission electron micrograph, at a magnification of90,000 times, of the ultra-low molecular weight polymer of Example 14(an ethylene/1-butene copolymer having a density of 0.887 g/cm³ and amelt viscosity at 350° F. of 5000 centipoise);

FIG. 10 is a bar chart depicting the population of lamella havinglengths in the indicated ranges for the ethylene/octene copolymers forwhich the transmission electron micrographs are set forth in FIGS. 3(a),3(b), 3(c), and 3(d), as determined by digital image analysis;

FIG. 11 is a bar chart depicting the frequency of lamella having lengthsin the indicated ranges for the ethylene/1-octene copolymers for whichthe transmission electron micrographs are set forth in FIGS. 3(a), 3(b),3(c), and 3(d), i.e., the percentage of total lamella which have lengthsin the indicated ranges, as determined by digital image analysis.

FIG. 12 is a compilation of the melting curves, as determined bydifferential scanning calorimetry, for the ethylene/1-octene copolymersfor which the transmission electron micrographs are set forth in FIGS.3(a), 3(b), 3(c), and 3(d);

FIG. 13 is a compilation of the crystallization curves, as determined bydifferential scanning calorimetry, for the ethylene/1-octene copolymersfor which the transmission electron micrographs are set forth in FIGS.3(a), 3(b), 3(c), and 3(d);

FIG. 14 is a compilation of the melting curves, as determined bydifferential scanning calorimetry, for the ethylene/1-octene copolymersof Comparative Examples G and H and of Examples 8 and 10;

FIG. 15 is a compilation of the crystallization curves obtained bydifferential scanning calorimetry for the ethylene/1-octene copolymersof Comparative Examples G and H and of Examples 8 and 10;

FIG. 16 is a plot of the total percent crystallinity ofethylene/1-octene and ethylene/1-butene copolymers of the inventionversus the density of such copolymers; and

FIG. 17 is a transmission electron micrograph, at a magnification of90,000 times, of the ultra-low molecular weight polymer of Example 19(an ethylene/1-octene copolymer having a density of 0.920 g/cm³, an Mnof 9800, and a melt viscosity at 350° F. of 5620 centipoise.

TEST PROCEDURES

Unless indicated otherwise, the following testing procedures are to beemployed:

Density is measured in accordance with ASTM D-792. The samples areannealed at ambient conditions for 24 hours before the measurement istaken.

Melt index (I₂), is measured in accordance with ASTM D-1238, condition190° C./2.16 kg (formally known as “Condition (E)”).

Molecular weight is determined using gel permeation chromatography (GPC)on a Waters 150° C. high temperature chromatographic unit equipped withthree mixed porosity columns (Polymer Laboratories 103, 104, 105, and106), operating at a system temperature of 140° C. The solvent is1,2,4-trichlorobenzene, from which 0.3 percent by weight solutions ofthe samples are prepared for injection. The flow rate is 1.0 mL/min. andthe injection size is 100 microliters.

The molecular weight determination is deduced by using narrow molecularweight distribution polystyrene standards (from Polymer Laboratories) inconjunction with their elution volumes. The equivalent polyethylenemolecular weights are determined by using appropriate Mark-Houwinkcoefficients for polyethylene and polystyrene (as described by Williamsand Word in Journal of Polymer Science, Polymer Letters, Vol. 6, (621)1968, incorporated herein by reference) to derive the followingequation:

M_(polyethylene)=a*(M_(polystyrene))b.

In this equation, a=0.4316 and b=1.0. Weight average molecular weight,M_(w), is calculated in the usual manner according to the followingformula: M_(w)=Σw_(i)*M_(i), where w_(i) and M_(i) are the weightfraction and molecular weight, respectively, of the ith fraction elutingfrom the GPC column.

Melt viscosity is determined in accordance with the following procedureusing a Brookfield Laboratories DVII+Viscometer in disposable aluminumsample chambers. The spindle used is a SC-31 hot-melt spindle, suitablefor measuring viscosities in the range of from 10 to 100,000 centipoise.A cutting blade is employed to cut samples into pieces small enough tofit into the 1 inch wide, 5 inches long sample chamber. The sample isplaced in the chamber, which is in turn inserted into a BrookfieldThermosel and locked into place with bent needle-nose pliers. The samplechamber has a notch on the bottom that fits the bottom of the BrookfieldThermosel to ensure that the chamber is not allowed to turn when thespindle is inserted and spinning. The sample is heated to 350° F., withadditional sample being added until the melted sample is about 1 inchbelow the top of the sample chamber. The viscometer apparatus is loweredand the spindle submerged into the sample chamber. Lowering is continueduntil brackets on the viscometer align on the Thermosel. The viscometeris turned on, and set to a shear rate which leads to a torque reading inthe range of 30 to 60 percent. Readings are taken every minute for about15 minutes, or until the values stabilize, which final reading isrecorded.

Percent crystallinity is determined by differential scanning calorimetryusing a Perkin-Elmer DSC 7. The percent crystallinity may be calculatedwith the equation:

% C=(A/292 J/g)×100,

wherein %C represents the percent crystallinity and A represents theheat of fusion of the ethylene in Joules per gram (J/g).

DETAILED DESCRIPTION

The ultra-low molecular weight ethylene polymer of the invention will bea homopolymer or an interpolymer of ethylene with at least oneethylenically unsaturated monomer, conjugated or nonconjugated diene,polyene, etc. The term “interpolymer” is used herein to indicate acopolymer, or a terpolymer, or the like. That is, at least one othercomonomer is polymerized with ethylene to make the interpolymer.

When the ultra-low molecular weight ethylene polymer is an interpolymer,preferred comonomers include the C₃-C₂₀ α-olefins, especially propene,isobutylene, 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene. Otherpreferred monomers include styrene, or alkyl-substituted styrenes,tetrafluoroethylene, vinylbenzocyclobutene, 1,4-hexadiene, andnaphthenics (e.g., cyclopentene, cyclohexene and cyclooctene).

The ultra-low molecular weight ethylene polymers of the invention willbe characterized by a number average molecular weight of less than11,000, preferably less than 10,000. Using the process of the invention,number average molecular weights of less than 5000 may be obtained.However, typically, the number average molecular weight of the polymerswill be greater than 2500.

Number average molecular weight is related to the viscosity at 350° F.of the ultra-low molecular weight ethylene polymers. The ultra-lowmolecular weight ethylene polymers will be characterized by a meltviscosity at 350° F. of less than about 8200, preferably less than 6000,with melt viscosities at 350° F. of less than about 600 centipoise beingeasily attained.

Further, the number average molecular weight of the ultra-low molecularweight ethylene polymers is related to the melt index (I₂). Note,however, that for the ultra-low molecular weight ethylene polymers ofthe invention, melt index is not measured, but is calculated fromviscosity correlations. The ultra-low molecular weight ethylene polymerswill be characterized by a calculated melt index (I₂) at 190° C. ofgreater than 1000, preferably of greater than 1300, with polymers havingcalculated melt indices of at least 10,000 g/10 min. being easilyattained.

The ultra-low molecular weight ethylene polymers will typically have adensity of from 0.850 to 0.970 g/cm³. The density employed will be afunction of the end use application contemplated. For instance, when thepolymer is intended as a wax substitute, densities greater than 0.910,preferably greater than 0.920 g/cm³ will be appropriate. In contrast,when the polymer is intended as the strength-imparting component of anadhesive, densities less than 0.900 g/cm³, preferably less than 0.895g/cm³ will be appropriate. When the ultra-low molecular weight ethylenepolymer is an interpolymer of ethylene and an aromatic comonomer, suchas styrene, the density of the interpolymer will be less than 1.10g/cm³.

FIG. 1 sets forth simplified representations of the crystallinestructures of homogeneous ethylene/1-octene copolymers and homogeneousethylene homopolymers having an I₂ of 1 g/10 min., prepared with amonocyclopentadienyltitanium single site catalyst. In particular, FIG.1(a) depicts a homogeneous ethylene/1-octene copolymer having a densityof from 0.86 to 0.88 g/cm³; FIG. 1(b) depicts a homogeneousethylene/1-octene copolymer having a density of from 0.88 to 0.91 g/cm³;FIG. 1(c) depicts a homogeneous ethylene/1-octene copolymer having adensity of from 0.91 to 0.93 g/cm³; and FIG. 1(d) depicts a homogeneousethylene homopolymer having a density greater than 0.95 g/cm³. Thedepictions set forth in FIGS. 1(a), 1(b), 1(c), and 1(d) arerepresentative of what has been described as Type I, Type II, Type III,and Type IV morphology.

By way of background, short chain branches from the α-olefin comonomeron the ethylene/(α-olefin copolymer chain are too big to be incorporatedin the crystalline structure and thus interrupt the chainfolding/bundling process. When the chain length between comonomerinsertion points is shorter than twice the minimum thickness of lamellarcrystallites, the polymer chains by definition can no longer crystallizevia a chain-folding mechanism. Rather, the chain segments betweencomonomer insertion points may simply bundle together to form acrystalline hard segment. These bundled chains, known as fringedmicelles, have different characteristics than those crystallites formedby the chain-folding process, i.e., lamella.

Theoretically, the minimum thickness of a lamellar crystallite is about40 angstroms. See, e.g., D. R. Burfield and N. Kashiwa, Makromol. Chem.,186, 2657 (1985). Thus, the chain length between two comonomer insertionpoints must be at least 80 angstroms to form one fold in the lamellarcrystallite. Thus, the population, distribution, and size of thecomonomer along the polymer chain will dictate thechain-folding/bundling process and the resulting crystal morphology.Polymer density is an inverse function of comonomer incorporation.Accordingly, lower density polymers, having more comonomer incorporated,will have fewer carbons separating adjacent comonomer insertion points.Thus, as density decreases, the population of lamella likewisedecreases.

As the density of the polymer increases, and the number of comonomerinsertion points decreases, the length and number of the lamella grows.Further, as the density of the polymer increases, long lamella begin toform which may cause a point of entanglement between adjacent polymermolecules. Such an entangling lamellae is referred to as a “tie chain.”At even higher densities, the lamella arrange themselves as spherulites,i.e., the lamerella appear to radiate from common nuclei. It is believedthat residual catalyst provide a point of origin for the polymer chaincrystallizing from the polymer melt to grow.

FIG. 1(a) depicts what may be classified as a Type I morphology. Such amorphology is characterized by the presence of bundle-like crystals,i.e., fringed micelles 101. FIG. 1(b) depicts what may be classified asa Type II morphology. Such a morphology is characterized by the presenceof fringed micelles 101 and lamella 102. FIG. 1(c) depicts what may beclassified as a Type III morphology. Such a morphology is characterizedby a lack of fringed micelles and by the presence of thicker lamella102, tie chains 103, and spherulites (not shown). FIG. 1(d) depicts whatmay be classified as a Type IV morphology. Such a morphology ischaracterized by a lack of fringed micelles and tie chains, and by thepresence of still thicker lamella 102 and spherulites (not shown).

The ultra-low molecular weight ethylene polymers of the invention have acrystalline structure which is markedly different from that of thehigher molecular weight ethylene polymers depicted in FIGS. 1(a), 1(b),1(c), and 1(d). In particular, as evidenced by the transmission electronmicrographs set forth in FIGS. 3 through 9, the ultra-low molecularweight ethylene polymers of the invention have a molecular architecturewhich is suggestive of more highly crystalline segments thancharacteristic of higher molecular weight polymers of equivalentdensity.

For instance, on the basis of FIG. 1(a), homogeneous ethylene/1-octenecopolymers having a density of 0.870 g/cm³ and an I₂ of 1 g/10 min.would be expected to exhibit fringed micelles, but no lamella, whenviewed using transmission electron microscopy. However, (as shown inFIG. 3(c)), ultra-low molecular weight ethylene/1-octene polymers of theinvention which have a density of 0.871 g/cm³ and an Mn of 9100, and (asshown in FIG. 3(d)), ultra-low molecular weight ethylene/1-octenepolymers of the invention which have a density of 0.870 g/cm³ and an Mnof 4,300, exhibit both fringed micelles and a significant number oflamella, when viewed using transmission electron microscopy.

Further, on the basis of FIG. 1(d), homogeneous ethylene/1-octenecopolymers having a density of 0.960 g/cm³ and an I₂ of 1 g/10 min.would be expected to exhibit lamella and spherulites, when viewed usingtransmission electron microscopy. However, (as shown in FIG. 7(b)),ultra-low molecular weight ethylene/1-octene polymers of the inventionwhich have a density of 0.963 g/cm³ and an Mn of 8,000, and (as shown inFIG. 7(c)), ultra-low molecular weight ethylene/1-octene polymers of theinvention which have a density of 0.968 g/cm³ and an Mn of 3,700,exhibit no spherulites, but rather exhibit very long lamella, which arebelieved to result from epitaxial crystallization. Epitaxialcrystallization refers to the growth of a crystal upon an existingcrystalline substrate, wherein the newly formed crystal adopts thecrystalline structure of the substrate.

A comparison of the transmission electron micrographs of FIGS. 2(a) and2(b), of FIGS. 3(a), 3(b), 3(c), and 3(d), and of FIGS. 7(a), 7(b), and7(c) indicates that as the molecular weight of the polymer decreases,the number and length of the lamella increases. For instance, FIG. 2(b)shows that an ultra-low molecular weight ethylene/1-octene copolymer ofthe invention having a density of 0.855 g/cm³ and an Mn of 4,600 hasvisually identifiable lamella (in contrast to the model for polymershaving a density of 0.855 g/cm³ set forth in FIG. 1(a). Further, whilethe model set forth in FIG. 1(c) would suggest that a copolymer having adensity of 0.920 g/cm³ would be expected to have a crystalline structurecharacterized by the presence of lamella and spherulites, FIG. 6 showsthat an ultra-low molecular weight ethylene/1-octene polymer of theinvention having a density of 0.929 g/cm³ and an Mn of 8,900, has verylong lamella, which is suggestive of epitaxial crystallization.

The length and population of lamella for transmission electronmicrographs may be determined by digital analysis by means known in theart. Digital images of certain of the transmission electron micrographsmay be acquired using a Quantimet 570 digital image analyzer (availablefrom Leica, Inc.), through a CCD video camera. White top hat filters maybe applied to the optical micrographs before detection of the binaries,i.e., with the lamella showing white against a grey background. Thefilters may be varied in size as required by the lamellar size in themicrographs. Detection thresholds may be set by visually comparingresulting binaries with the original images. Minimal editing of thebinaries may be done to correct obvious omissions or inclusionsencountered in the detection process.

In the case of the ethylene/1-octene copolymers for which thetransmission electron micrographs are set forth in FIGS. 3(a), 3(b),3(c), and 3(d), the average length of the lamella detected and thenumber of lamella per cubic micrometer has been calculated. In the caseof FIG. 3(a), the average lamellar length is 30 nanometers, with apopulation of 20 lamella per cubic micrometer. In the case of FIG. 3(b),the average lamellar length is 54, with a population of 140 lamella percubic micrometer. In the case of FIG. 3(c), the average lamellar lengthis 59 nanometers, with a population of 240 lamella per cubic micrometer.In the case of FIG. 3(d), the average lamellar length is 66 nanometers,with a population of 381 lamella per cubic micrometer. These valuesindicate that ultra-low molecular weight ethylene/1-octene polymers ofthe invention, which have a density of about 0.870 g/cm³ and Mn's of9,100 and 4,300, respectively, have over 12 times and 40 times,respectively, as many lamella per cubic micrometer as do comparativepolymers having a density of 0.870 g/cm³ and an I₂ of 1 g/10 min.

FIG. 10 is a bar chart depicting the population of lamella havinglengths in the indicated ranges for the ethylene/octene copolymers forwhich the transmission electron micrographs are set forth in FIGS. 3(a),3(b), 3(c), and 3(d), as determined by digital image analysis. Table Asets forth numerically the data used to prepare FIG. 10.

TABLE A Data used in Preparation of FIG. 10 No. of No. of No. of No. oflamella lamella lamella lamella Lamellar per cubic per cubic per cubicper cubic length micron micron micron micron (nanometers) FIG. 3(d) FIG.3(c) FIG. 3(b) FIG. 3(a) less than 40 150 40 40 20 40-60 340 120 54 060-80 130 30 20 0  80-100 100 30 10 0 100-120 30 10 0 0 120-140 50 0 0 0140-160 10 5 0 0 160-180 10 0 0 0 180-200 10 0 5 0

As shown in FIG. 10 and Table A, ethylene/1-octene copolymers having adensity of 0.870 g/cm³ and an I₂ of 1 g/10 min., while they have someimages with an aspect ratio greater than 3 (they have 20 lamella percubic micron having a length less than 40 nanometers), they do not haveany lamella greater than 40 nanometers in length. As also shown,ethylene/1-octene copolymers having a density of 0.875 g/cm³ and an I₂of 246 g/10 min. have twice as many lamella less than 40 nanometers inlength than copolymers having an I₂ of 1 g/10 min., and exhibit lamellain the ranges of 40-60, 60-80, and 80-100 nanometers in length (with nosignificant number of lamella having a length greater than 100nanometers). As also shown, ethylene/1-octene copolymers having adensity of 0.871 g/cm³ and an Mn of 9,100, have 2.2 times as manylamella having a length from 40-60 nanometers and 3 times as manylamella having a length of from 80 to 100 nanometers thanethylene/octene copolymers having a density of 0.875 g/cm³ and an I₂ of246 g/10 min. As also shown, ethylene/1-octene copolymers having adensity of 0.870 g/cm³ and an Mn of 4,300, have over 6 times as manylamella having a length from 40-60 nanometers, 6 times as many lamellahaving a length from 60-80 nanometers, and 9.5 times as many lamellahaving a length of from 80 to 100 nanometers than ethylene/1-octenecopolymers having a density of 0.875 g/cm³ and an I₂ of 246 g/10 min.Moreover, the ethylene/octene copolymers having a density of 0.870 g/cm³and an Mn of 4,300, have significant numbers of lamella in the ranges of100-120 and 120-140 nanometers.

FIG. 11 is a bar chart depicting the frequency of lamella having lengthsin the indicated ranges for the ethylene/1-octene copolymers for whichthe transmission electron micrographs are set forth in FIGS. 3(a), 3(b),3(c), and 3(d), i.e., the percentage of the total number of lamellawhich have lengths in the indicated ranges, as determined by digitalimage analysis. Table B sets forth numerically the data used to prepareFIG. 11.

TABLE B Data used in Preparation of FIG. 11 Percent of Percent ofPercent of Percent of lamella lamella lamella lamella having havinghaving having length in length in length in length in Lamellar indicatedindicated indicated indicated length range range range range(nanometers) FIG. 3(d) FIG. 3(c) FIG. 3(b) FIG. 3(a) less than 40 18 2030 100 40-60 41 51 40 0 60-80 16 10 20 0  80-100 12 10 8 0 100-120 3 4 00 120-140 6 0 0 0 140-160 1 2 0 0 160-180 1 0 0 0 180-200 1 0 4 0

More specifically, FIG. 11 shows that for an ultra-low densityethylene/1-octene copolymer of the invention which has a density of0.871 g/cm³ and an Mn of 9,100, 80 percent of the lamella have a lengthgreater than 40 nanometers, with 50 percent of the lamella having alength between 40 and 60 nanometers, over 10 percent of the lamellahaving a length between 60 and 80 nanometers, and over 10 percent of thelamella having a length between 80 and 100 nanometers. Further, FIG. 11shows that for an ultra-low density ethylene/1-octene copolymer of theinvention which has a density of 0.870 g/cm³ and an Mn of 4,300, over 80percent of the lamella have a length greater than 40 nanometers, withover 40 percent of the lamella having a length of from 40 to 60nanometers, 16 percent of the lamella having a length of from 60 to 80nanometers, 12 percent of the lamella having a length of from 80 to 100nanometers, and over 10 percent of the lamella having a length greaterthan 100 nanometers.

At higher densities, the ultra-low molecular weight ethylene polymers ofthe invention likewise exhibit a crystalline structure which is markedlydifferent from that of higher molecular weight comparative materials.For instance, FIG. 5 reveals that while an ethylene/octene copolymerhaving a density of 0.915 g/cm³ and an I₂ of 1 g 10 min. has lamella,some of which appear entangled, i.e., a crystalline organization whichcorresponds to the Type III structure set forth in FIG. 1(c). Incontrast, FIG. 6 reveals that an ethylene/octene copolymer having adensity of 0.929 g/cm³ and an Mn of 8,900, is characterized by longlamella indicative of epitaxial crystallization. The contrast betweenultra-low molecular weight materials and high molecular weightmaterials, at higher polymer densities, is especially striking in FIGS.7(a), 7(b), and 7(c).

The greater proportion of more highly crystalline materials (and greaterproportion of more highly amorphous materials) characteristic of theultra-low molecular weight ethylene polymers of the invention arereflected in the physical properties of the polymer, such as the meltingand crystallization behavior. FIG. 12 is a compilation of the meltingcurves obtained by differential scanning calorimetry for theethylene/1-octene copolymers for which the transmission electronmicrographs are set forth in FIGS. 3(a), 3(b), 3(c), and 3(d). FIG. 13is a compilation of the crystallization curves obtained by differentialscanning calorimetry for the ethylene/1-octene copolymers for which thetransmission electron micrographs are set forth in FIGS. 3(a), 3(b),3(c), and 3(d). FIG. 14 is a compilation of the melting curves obtainedby differential scanning calorimetry for the ethylene/1-octenecopolymers of Comparative Examples G and H and of Examples 8 and 10.FIG. 15 is a compilation of the crystallization curves obtained bydifferential scanning calorimetry for the ethylene/1-octene copolymersof Comparative Examples G and H and of Examples 8 and 10.

As illustrated in FIGS. 12 and 14, as the molecular weight of thecopolymer decreases, the melting behavior broadens and the peak meltingtemperature shifts to the right. As illustrated in FIGS. 13 and 15, asthe molecular weight of the copolymer decreases, the crystalline meltingpoint likewise shifts to the right. FIGS. 12 through 15 support theconclusion that the lower molecular weight of the invention have greaterproportions of more highly crystalline materials (and greater portionsof more highly amorphous materials) than their higher molecular weightcounterparts. This suggests that the ultra-low molecular weightmaterials of the invention will begin to crystallize at highertemperatures than corresponding higher molecular weight materials havingan equivalent density. This leads to utility in applications where thepolymer or formulation must solidify quickly (such as in hot meltadhesives) or must maintain its structural integrity upon application ofheat (such as in shoe soles which arc intended for consumer machinewashing and drying at elevated temperatures).

Likewise, the selection of comonomer affects the high temperatureperformance of the ultra-low molecular weight polymers of the invention.In particular, as the length of the comonomer chain increases, thepercent crystallinity as determined by DSC likewise increases whendensity and melt index are held constant. For instance, FIG. 16 showsthat an ethylene/1-octene polymer of the invention having a density of0.883 g/cm³ and a melt viscosity at 350° F. of 5000 centipoise (Mn of8,200) has a greater total percent crystallinity than anethylene/1-butene copolymer of the invention having a density of 0.887g/cm³ and a melt viscosity at 350° F. of 5000 centipoise, e.g., 28.18versus 26.39 percent. Accordingly, when an α-olefin comonomer isemployed, such comonomer will preferably be a C₄-C₂₀ α-olefin, morepreferably a C₅-C₂₀ α-olefin, and most preferably a C₆-C₂₀ α-olefin.

The ultra-low molecular weight ethylene polymers of the invention arecharacterized as being non-pourable. That is, the ultra-low molecularweight ethylene polymers of the invention are characterized as having apour point greater than −30° C. as determined by ASTM D-97. Preferably,the pour point of the ultra-low molecular weight ethylene polymers willbe greater than room temperature (25° C.), and more preferably greaterthan 50° C.

The ultra-low molecular weight ethylene polymers of the invention may beethylene homopolymers or interpolymers of ethylene and at least onesuitable comonomer. Preferred comonomers include C₃₋₂₀ α-olefins(especially ethylene, propylene, isobutylene, 1-butene, 1-hexene,3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene, and 1-octene), C₄₋₄₀)non-conjugated dienes, styrene, alkyl-substituted styrene,tetrafluoroethylene, naphthenics, and mixtures thereof.

When ethylene propylene diene terpolymers (EPDM's) are prepared, thedienes are typically non-conjugated dienes having from 6 to 15 carbonatoms. Representative examples of suitable non-conjugated dienes thatmay be used to prepare the terpolymers include:

(a) Straight chain acyclic dienes such as 1,4-hexadiene; 1,5-heptadiene;and 1,6-octadiene;

(b) Branched chain acyclic dienes such as 5-methyl-1,4-hexadiene;3,7-dimethyl-1,6-octadiene; and 3,7-dimethyl-1,7-octadiene;

(c) Single ring alicyclic dienes such as 4-vinylcyclohexene;1-allyl-4-isopropylidene cyclohexane; 3-allylcyclopentene;4-allylcyclohexene; and 1-isopropenyl-4-butenylcyclohexene;

(d) Multi-ring alicyclic fused and bridged ring dienes such asdicyclopentadiene; alkenyl, alkylidene, cycloalkenyl, andcycloalkylidene norbornenes, such as 5-methylene-2-norbornene;5-methylene-6-methyl-2-norbornene;5-methylene-6,6-dimethyl-2-norbornene; 5-propenyl-2-norbornene;5-(3-cyclopentenyl)-2-norbornene; 5-ethylidene-2-norbornene;5-cyclohexylidene-2-norbornene; etc.

The preferred dienes are selected from the group consisting of1,4-hexadiene; dicyclopentadiene; 5-ethylidene-2-norbornene;5-methylene-2-norbornene; 7-methyl-1,6 octadiene; 4-vinylcyclohexene;etc. One preferred conjugated diene which may be employed is piperylene.

Most preferred monomers are ethylene, mixtures of ethylene, propyleneand ethylidenenorbornene, or mixtures of ethylene and a C₄₋₈ α-olefin,more especially a C₆-C₈, and most especially 1-octene.

The ultra-low molecular weight ethylene polymers of the invention may beprepared using a constrained geometry catalyst. Constrained geometrymetal complexes and methods for their preparation are disclosed in U.S.application Ser. No. 545,403, filed Jul. 3, 1990 (EP-A-416,815); U.S.application Ser. No. 702,475, filed May 20, 1991 (EP-A-514,828); as wellas U.S. Pat. Nos. 5,470,993, 5,374,696, 5,231,106, 5,055,438, 5,057,475,5,096,867, 5,064,802, and 5,132,380. In U.S. Ser. No. 720,041, filedJun. 24, 1991, (EP-A-514,828) certain borane derivatives of theforegoing constrained geometry catalysts are disclosed and a method fortheir preparation taught and claimed. In U.S. Pat. No. 5,453,410combinations of cationic constrained geometry catalysts with analumoxane were disclosed as suitable olefin polymerization catalysts.For the teachings contained therein, the aforementioned pending UnitedStates Patent applications, issued United States Patents and publishedEuropean Patent Applications are herein incorporated in their entiretyby reference thereto.

Exemplary constrained geometry metal complexes in which titanium ispresent in the +4 oxidation state include but are not limited to thefollowing:(n-butylamido)dimethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(IV) dimethyl;(n-butylamido)dimethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(IV) dibenzyl;(t-butylamido)dimethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(IV) dimethyl;(t-butylamido)dimethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(IV) dibenzyl;(cyclododecylamido)dimethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(IV) dibenzyl;(2,4,6-trimethylanilido)dimethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(IV) dibenzyl;(1-adamantylamido)dimethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(IV) dibenzyl;(t-butylamido)dimethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(IV) dimethyl;(t-butylamido)dimethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(IV) dibenzyl;(1-adamantylamido)dimethyl(η⁵-tetramethylcyclopentadienyl)-silanetitanium(IV) dimethyl;(n-butylamido)diisopropoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(IV)dimethyl;(n-butylamido)diisopropoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(IV) dibenzyl;(cyclododecylamido)diisopropoxy(η⁵-tetramethylcyclopentadienyl)-silanetitanium(IV) dimethyl;(cyclododecylamido)diisopropoxy(η⁵-tetramethylcyclopentadienyl)-silanetitanium(IV) dibenzyl;(2,4,6-trimethylanilido)diisopropoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(IV) dimethyl;(2,4,6-trimethylanilido)diisopropoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(IV) dibenzyl;(cyclododecylamido)dimethoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(IV) dimethyl;(cyclododecylamido)dibethoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(IV) dibenzyl;(1-adamantylamido)diisopropoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(IV) dimethyl;(1-adamantylamido)diisopropoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(IV) dibenzyl;(n-butylamido)dimethoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(IV) dimethyl;(n-butylamido)dimethoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(IV) dibenzyl;(2,4,6-trimethylanilido)dimethoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(IV) dimethyl;(2,4,6-trimethylanilido)dimethoxy(η⁵-tetramethylcyclopentadienyl)silanetitaniumtitanium (IV) dibenzyl;(1-adamantylamido)dimethoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(IV) dimethyl;(1-adamantylamido)dimethoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(IV) dibenzyl;(n-butylamido)ethoxymethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(IV) dimethyl;(n-butylamido)ethoxymethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(IV) dibenzyl;(cyclododecylamido)ethoxymethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(IV) dimethyl;(cyclododecylamido)ethoxymethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(IV) dibenzyl;(2,4,6-trimethylanilido)ethoxymethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(IV) dimethyl;(2,4,6-trimethylanilido)ethoxymethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(IV) dibenzyl;(cyclododecylamido)dimethyl(η⁵-tetramethylcyclopentadienyl)silane-titanium(IV) dimethyl;(1-adamantylamido)-ethoxymethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(IV) dimethyl; and(1-adamantylamido)ethoxymethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(IV) dibenzyl.

Exemplary constrained geometry metal complexes in which titanium ispresent in the +3 oxidation state include but are not limited to thefollowing:(n-butylamido)dimethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(III) 2-(N,N-dimethylamino)benzyl;(t-butylamido)dimethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(III) 2-(N,N-dimethylamino)benzyl;(cyclododecylamido)dimethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(III) 2-(N,N-dimethylamino)benzyl;(2,4,6-trimethylanilido)dimethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(III) 2-(N,N-dimethylamino)benzyl;(1-adamantylamido)dimethyl(η5-tetramethylcyclopentadienyl)silanetitanium(III) 2-(N,N-dimethylamino)benzyl;(t-butylamido)dimethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(III) 2-(N,N-dimethylamino)benzyl;(n-butylamido)diisopropoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(III) 2-(N,N-dimethylamino)benzyl;(cyclododecylamido)diisopropoxy(η⁵-tetramethylcyclopentadienyl)-silanetitanium(III) 2-(N,N-dimethylamino)benzyl;(2,4,6-trimethylanilido)diisopropoxy(η⁵-2-methylindenyl)silanetitanium(III) 2-(N,N-dimethylamino)benzyl;(1-adamantylamido)diisopropoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(III) 2-(N,N-dimethylamino)benzyl;(n-butylamido)dimethoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(III) 2-(N,N-dimethylamino)benzyl;(cyclododecylamido)dimethoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(III) 2-(N,N-dimethylamino)benzyl;(1-adamantylamido)dimethoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(III) 2-(N,N-dimethylamino)benzyl;(2,4,6-trimethylanilido)dimethoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(III) 2-(N,N-dimethylamino)benzyl;(n-butylamido)ethoxymethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(III) 2-(N,N-dimethylamino)benzyl;(cyclododecylamido)ethoxymethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(III) 2-(N,N-dimethylamino)benzyl;(2,4,6-trimethylanilido)ethoxymethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(III) 2-(N,N-dimethylamino)benzyl; and(1-adamantylamido)ethoxymethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(III) 2-(N,N-dimethylamino)benzyl.

Exemplary constrained geometry metal complexes in which titanium ispresent in the +2 oxidation state include but are not limited to thefollowing: (n-butylamido)dimethyl(η⁵tetramethylcyclopentadienyl)silane-titanium (II)1,4-diphenyl-1,3-butadiene;(n-butylamido)dimethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(II) 1,3-pentadiene;(t-butylamido)dimethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(II)1,4-diphenyl-1,3-butadiene;(t-butylamido)dimethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(II)(1,3-pentadiene;(cyclododecylamido)dimethyl(η5-tetramethylcyclopentadienyl)silanetitanium (II)1,4-diphenyl-1,3-butadiene;(cyclododecylamido)dimethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(II) 1,3-pentadiene;(2,4,6-trimethylanilido)dimethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(II),1,4-diphenyl-1,3-butadiene;(2,4,6-trimethylanilido)dimethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(II) 1,3-pentadiene;(2,4,6-trimethylanilido)dimethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(IV) dimethyl;(1-adamantylamido)dimethyl(η5-tetramethylcyclopentadienyl)silane-titanium(II)1,4-diphenyl-1,3-butadiene;(1-adamantylamido)dimethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(II) 1,3-pentadiene;(t-butylamido)dimethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(II) 1,4-diphenyl-1,3-butadiene;(t-butylamido)dimethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(II) 1,3-pentadiene;;(n-butylamido)diisopropoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(II) 1,4-diphenyl-1,3-butadiene;(n-butylamido)diisopropoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(II) 1,3-pentadiene;(cyclododecylamido)diisopropoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(II) 1,4-diphenyl-1,3-butadiene;(cyclododecylamido)diisopropoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(II) 1,3-pentadiene;(2,4,6-trimethylanilido)diisopropoxy(η⁵-2-methylindenyl)silanetitanium(II) 1,4-diphenyl-1,3-butadiene; (2,4,6-trimethylanilido)diisopropoxy(η⁵tetramethylcyclopentadienyl)silanetitanium (II) 1,3-pentadiene;(1-adamantylamido)diisopropoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium (II)1,4-diphenyl-1,3-butadiene;(1-adamantylamido)diisopropoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(II) 1,3-pentadiene;(n-butylamino)dimethoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(II) 1,4-diphenyl-1,3-butadiene;(n-butylamido)dimethoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(II) 1,3-pentadiene;(cyclododecylamido)dimethoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(II) 1,4-diphenyl-1,3-butadiene;(cyclododecylamido)dimethoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(II) 1,3-pentadiene;(2,4,6-trimethylanilido)dimethoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(II) 1,4-diphenyl-1,3-butadiene;(2,4,6-trimethylanilido)dimethoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(II) 1,3-pentadiene;(1-adamantylamido)dimethoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(II) 1,4-diphenyl-1,3-butadiene;(1-adamantylamido)dimethoxy(η⁵-tetramethylcyclopentadienyl)silanetitanium(II) 1,3-pentadiene;(n-butylamido)ethoxymethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(II) 1,4-diphenyl-1,3-butadiene;(n-butylamido)ethoxymethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(II) 1,3-pentadiene;(cyclododecylamido)ethoxymethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(II) 1,4-diphenyl-1,3-butadiene;(cyclododecylamido)ethoxymethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(II) 1,3-pentadiene;(2,4,6-trimethylanilido)ethoxymethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(II) 1,4-diphenyl-1,3-butadiene;(2,4,6-trimethylanilido)ethoxymethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(II) 1,3-pentadiene;(1-adamantylamido)ethoxymethyl(η⁵-tetramethylcyclopentadienyl)silanetitanium(II) 1,4-diphenyl-1,3-butadiene; and (1-adamantylamido)ethoxymethyl(T5-tetramethylcyclopentadienyl)silanetitanium (11) 1,3-pentadiene.

The complexes can be prepared by use of well known synthetic techniques.The reactions are conducted in a suitable noninterfering solvent at atemperature from −100 to 300° C., preferably from −78 to 100° C., mostpreferably from 0 to 50° C. A reducing agent may be used to cause themetal to be reduced from a higher to a lower oxidation state. Examplesof suitable reducing agents are alkali metals, alkaline earth metals,aluminum and zinc, alloys of alkali metals or alkaline earth metals suchas sodium/mercury amalgam and sodium/potassium alloy, sodiumnaphthalenide, potassium graphite, lithium alkyls, lithium or potassiumalkadienyls, and Grignard reagents.

Suitable reaction media for the formation of the complexes includealiphatic and aromatic hydrocarbons, ethers, and cyclic ethers,particularly branched-chain hydrocarbons such as isobutane, butane,pentane, hexane, heptane, octane, and mixtures thereof; cyclic andalicyclic hydrocarbons such as cyclohexane, cycloheptane,methylcyclohexane, methylcycloheptane, and mixtures thereof; aromaticand hydrocarbyl-substituted aromatic compounds such as benzene, toluene,and xylene, C₁₋₄ dialkyl ethers, C₁₋₄ dialkyl ether derivatives of(poly)alkylene glycols, and tetrahydrofuran. Mixtures of the foregoingare also suitable.

Suitable activating cocatalysts and activating techniques have beenpreviously taught with respect to different metal complexes in thefollowing references: EP-A- 277,003, U.S. Pat. Nos. 5,153,157,5,064,802, EP-A-468,651 (equivalent to U.S. Ser. No. 07/547,718),EP-A-520,732 (equivalent to U.S. Ser. No. 07/876,268), WO 95/00683(equivalent to U.S. Ser. No. 08/82,201), and EP-A-520,732 (equivalent toU.S. Ser. No. 07/884,966 filed May 1, 1992), the teachings of which arehereby incorporated by reference.

Suitable activating cocatalysts for use herein include perfluorinatedtri(aryl)boron compounds, and most especiallytris(pentafluorophenyl)borane; nonpolymeric, compatible,noncoordinating, ion forming compounds (including the use of suchcompounds under oxidizing conditions), especially the use of ammonium-,phosphonium-, oxonium-, carbonium-, silyllum- or sulflonium- salts ofcompatible, noncoordinating anions, and ferrocenium salts of compatible,noncoordinating anions. Suitable activating techniques include the useof bulk electrolysis (explained in more detail hereinafter). Acombination of the foregoing activating cocatalysts and techniques maybe employed as well.

Illustrative, but not limiting, examples of boron compounds which may beused as an activating cocatalysts are: tri-substituted ammonium saltssuch as:

trimethylammonium tetrakis(pentafluoro-phenyl)borate; triethylammoniumtetrakis(pentafluorophenyl)borate; tripropylammoniumtetrakis(pentafluorophenyl)borate; tri(n-butyl)ammoniumtetrakis(pentafluorophenyl) borate; tri(sec-butyl)ammoniumtetrakis(pentafluoro-phenyl)borate; N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate; N,N-dimethylaniliniumn-butyltris(pentafluorophenyl)borate; N,N-dimethylaniliniumbenzyltris(pentafluorophenyl)borate; N,N-dimethylaniliniumtetrakis(4-(t-butyldimethylsilyl)-2,3,5,6-tetrafluorophenyl)borate;N,N-dimethylaniliniumtetrakis(4-(trilsopropylsilyl)-2,3,5,6-tetrafluorophenyl)borate;N,N-dimethylanilinium pentafluorophenoxytris(pentafluorophenyl)borate;N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate;N,N-dimethyl-2,4,6-trimethylanilinium tetrakis(pentafluorophenyl)borate;trimethylammonium tetrakis(2,3,4,6-tetrafluorophenyl)borate;triethylammonium tetrakis(2,3,4,6-tetrafluorophenyl) borate;tripropylammonium tetrakis(2,3,4,6-tetrafluorophenyl) borate;tri(n-butyl)ammonium tetrakis(2,3,4,6-tetrafluorophenyl)borate;dimethyl(t-butyl)ammonium tetrakis(2,3,4,6-tetrafluorophenyl)borate;N,N-dimethylanilinium tetrakis(2,3,4,6-tetrafluorophenyl)borate;N,N-diethylanililnium tetrakis(2,3,4,6-tetrafluorophenyl)borate; andN,N-diethyl-2,4,6-trimethylaniliniumtetrakis(2,3,4,6-tetrafluorophenyl)borate;

disubstituted ammonium salts such as: di-(i-propyl)ammoniumtetrakis(pentafluoro-phenyl)borate; and dicyclohexylammoniumtetrakis(pentafluorophenyl)borate;

trisubstituted phosphonium salts such as: triphenylphosphoniumtetrakis(pentafluoro-phenyl)borate; tri(o-tolyl)phosphoniumtetrakis(pentafluorophenyl)borate; andtri(2,6-dimethylphenyl)phosphonium tetrakis(pentafluorophenyl)borate;

disubstituted oxonium salts such as: diphenyloxoniumtetrakis(pentafluoro-phenyl)borate; di(o-tolyl)oxoniumtetrakis(pentafluorophenyl) borate; and di(2,6-dimethylphenyl)oxoniumtetrakis(pentafluorophenyl)borate; and

disubstituted sulfonium salts such as: diphenylsulfoniumtetrakis(pentafluorophenyl)borate; di(o-tolyl)sulfoniumtetrakis(pentafluorophenyl)borate; and bis(2,6-dimethylphenyl)sulfoniumtetrakis(pentafluorophenyl)borate.

A most preferred activating cocatalyst is trispentafluorophenylborane.

Alumoxanes, especially methylalumoxane or triisobutylaluminum modifiedmethylalumoxane are also suitable activators and may be used foractivating the present metal complexes.

The molar ratio of metal complex: activating cocatalyst employedpreferably ranges from 1:1000 to 2:1, more preferably from 1:5 to 1.5:1,most preferably from 1:2 to 1:1. In the preferred case in which a metalcomplex is activated by trispentafluorophenylborane andtriisobutylaluminum modified methylalumoxane, thetitanium:boron:aluminum molar ratio is typically from 1:10:50 to1:0.5:0.1, most typically from about 1:3:5.

A support, especially silica, alumina, or a polymer (especiallypoly(tetrafluoroethylene) or a polyolefin) may be employed, anddesirably is employed when the catalysts are used in a gas phasepolymerization process. The support is preferably employed in an amountto provide a weight ratio of catalyst (based on metal):support from1:100,000 to 1:10, more preferably from 1:50,000 to 1:20, and mostpreferably from 1:10,000 to 1:30.

At all times, the individual ingredients as well as the recoveredcatalyst components must be protected from oxygen and moisture.Therefore, the catalyst components and catalysts must be prepared andrecovered in an oxygen and moisture free atmosphere. Preferably,therefore, the reactions are performed in the presence of an dry, inertgas such as, for example, nitrogen.

In general, the polymerization may be accomplished at conditions forZiegler-Natta or Kaminsky-Sinn type polymerization reactions, that is,reactor pressures ranging from atmospheric to 3500 atmospheres. Thereactor temperature should be greater than 80° C., typically from 100°C. to 250° C., and preferably from 100° C. to 150° C., with higherreactor temperatures, i.e., reactor temperatures greater than 100° C.generally favoring the formation of lower molecular weight polymers.

In conjunction with the reactor temperature, the hydrogen:ethylene molarratio influences the molecular weight of the polymer, with greaterhydrogen levels leading to lower molecular weight polymers. When thedesired polymer has an I₂ of 1g/10 min, the hydrogen:ethylene molarratio will typically be 0:1. When the desired polymer has an I₂ of 1000g/10 min., the hydrogen:ethylene molar ratio will typically be from0.45:1 to 0.7:1. The upper limit of the hydrogen:ethylene molar ratio isabout 2.2-2.5:1.

Generally the polymerization process is carried out with a differentialpressure of ethylene of from about 10 to about 1000 psi (70 to 7000kPa), most preferably from about 40 to about 60 psi (30(to 400 kPa). Thepolymerization is generally conducted at a temperature of from 80 to250° C., preferably from 90 to 170° C., and most preferably from greaterthan 95 to 140° C.

In most polymerization reactions the molar ratio ofcatalyst:polymerizable compounds employed is from 10⁻¹²:1 to 10 ⁻¹:1,more preferably from 10⁻⁹:1 to 10⁻⁵:1.

Solution polymerization conditions utilize a solvent for the respectivecomponents of the reaction. Preferred solvents include mineral oils andthe various hydrocarbons which are liquid at reaction temperatures.Illustrative examples of useful solvents include alkanes such aspentane, isopentane, hexane, heptane, octane and nonane, as well asmixtures of alkanes including kerosene and Isopar E™, available fromExxon Chemicals Inc.; cycloalkanes such as cyclopentane and cyclohexane;and aromatics such as benzene, toluene, xylones, ethylbenzene anddiethylbenzene.

The solvent will be present in an amount sufficient to prevent phaseseparation in the reactor. As the solvent functions to absorb heat, lesssolvent leads to a less adiabatic reactor. The solvent:ethylene ratio(weight basis) will typically be from 2.5:1 to 12:1, beyond which pointcatalyst efficiency suffers. The most typical solvent:ethylene ratio(weight basis) is in the range of from 5:1 to 10:1.

The polymerization may be carried out as a batchwise or a continuouspolymerization process, with continuous polymerizations processes beingrequired for the preparation of substantially linear polymers. In acontinuous process, ethylene, comonomer, and optionally solvent anddiene are continuously supplied to the reaction zone and polymer productcontinuously removed therefrom.

The ultra-low molecular weight polymers of the invention may further bemade in a slurry polymerization process, using the catalysts asdescribed above as supported in an inert support, such as silica. As apractical limitation, slurry polymerization takes place in liquiddiluents in which the polymer product is substantially insoluble.Typically, the diluent for slurry polymerization is one or morehydrocarbons with less than 5 carbon atoms. If desired, saturatedhydrocarbons such as ethane, propane or butane may be used in whole orpart as the diluent. Likewise the comonomer or a mixture of differentcomonomers may be used in whole or part as the diluent.

Typically, the diluent comprises in at least major part the comonomer(s)to be polymerized.

The ultra-low molecular weight polymers of the invention may bepolymerized in a first reactor, with a second polymer (of highermolecular weight and/or of different density, and/or which isheterogeneous) being polymerized in a second reactor which is connectedin series or in parallel to that in which the ultra-low molecular weightpolymer is produced, to prepare in-reactor polymer blends havingdesirable properties. An example of a dual reactor process which may beadapted in accordance with the teachings of this disclosure to prepareblends wherein at least one component is an ultra-low molecular weightpolymer of this invention, is disclosed in WO 94/00500, equivalent toU.S. Ser. No. 07/904,770, as well as U.S. Ser. No. 08/10958, filed Jan.29, 1993, the teachings of which are incorporated herein by reference.

Additives such as antioxidants (e.g., hindered phenolics (e.g., Irganox™1010, Irganox™ 1076), phosphites (e.g., Irgafos™ 168)), antiblockadditives, pigments, fillers, and the like can also be included in themodified formulations, to the extent that they do not interfere with thedesired formulation properties.

The skilled artisan will appreciate that the invention disclosed hereinmay be practiced in the absence of any component which has not beenspecifically disclosed. The following examples are provided as furtherillustration of the invention and are not to be construed as limiting.Unless stated to the contrary au parts and percent ages are expressed ona weight basis.

Catalyst Preparation One

Part 1: Preparation of TiCl₃(DME)1.5

The apparatus (referred to as R-1) was set-up in the hood and purgedwith nitrogen; it consisted of a 10 L glass kettle with flush mountedbottom valve, 5-neck head, polytetrafluoroethylene gasket, clamp, andstirrer components (bearing, shaft, and paddle). The necks were equippedas follows: stirrer components were put on the center neck, and theouter necks had a reflux condenser topped with gas inlet/outlet, aninlet for solvent, a thermocouple, and a stopper. Dry, deoxygenateddimethoxyethane (DME) was added to the flask (approx. 5 L). In thedrybox, 700 g of TiCl₃ was weighed into an equalizing powder additionfunnel; the funnel was capped, removed from the drybox, and put on thereaction kettle in place of the stopper. The TiCl₃ was added over about10 minutes with stirring. After the addition was completed, additionalDME was used to wash the rest of the TiCl₃ into the flask. The additionfunnel was replaced with a stopper, and the mixture heated to reflux.The color changed from purple to pale blue. The mixture was heated forabout 5 hours, cooled to room temperature, the solid was allowed tosettle, and the supernatant was decanted from the solid. TheTiCl₃(DME)1.5 was left in R-1 as a pale blue solid.

Part 2: Preparation of[(Me₄C₅)SiMe₂N-t-Bu][MPCl]₂

The apparatus (referred to as R-2) was set-up as described for R-1,except that flask size was 30 L. The head was equipped with seven necks;stirrer in the center neck, and the outer necks containing condensertopped with nitrogen inlet/outlet, vacuum adapter, reagent additiontube, thermocouple, and stoppers. The flask was loaded with 4.5 L oftoluene, 1.14 kg of (Mt₄C₅H)Si₂NH-t-Bu, and 3.46 kg of 2 M i-PrMgCl inEt₂O. The mixture was then heated, and the other allowed to boil offinto a trap cooled to −78° C. After four hours, the temperature of themixture had reached 75° C. At the end of this time, the heater wasturned off and DME was added to the hot, stirring solution, resulting inthe formation of a white solid. The solution was allowed to cool to roomtemperature, the material was allowed to settle, and the supernatant wasdecanted from the solid. The [(Me₄C₅)SiMe₂N-t-Bu][MgCl]₂ was left in R-2as an off-white solid.

Part 3: Preparation of [(η⁵-ME₄C₅)Si Me ₂N-t-Bu]TiMe₂

The materials in R-1 and R-2 were slurried in DME (3 L of DME in R-1and5 L in R-2). The contents of R-1 were, transferred to R-2 using atransfer tube connected to the bottom valve of the 10 L flask and one ofthe head openings in the 30 L flask. The remaining material in R-1 waswashed over using additional DME. The mixture darkened quickly to a deepred/brown color, and the temperature in R-2 rose from 21° C. to 32° C.After 20 minutes, 160 mL of CH₂Ckl₂ was added through a dropping funnel,resulting in a color change to green/brown. This was followed by theaddition of 3.46 kg of 3 M MeMgCl in THF, which caused a temperatureincrease from 22° C. to 52° C. The mixture was stirred for 30 minutes,then 6 L of solvent was removed under vacuum. Isopar E (6 L) was addedto the flask. This vacuum/solvent addition cycle was repeated, with 4 Lof solvent removed and 5 L of Isopar E added. In the final vacuum step,an additional 1.2 L of solvent was removed. The material was allowed tosettle overnight, then the liquid layer decanted into another 30 L glasskettle (R-3). The solvent in R-3 was removed under vacuum to leave abrown solid, which was re-extracted with Isopar E; this material wastransferred into a storage cylinder. Analysis indicated that thesolution (17.23 L) was 0.1534 M in titanium; this is equal to 2.644moles of [(η⁵Me₄C₅)SiMe₂N-t-Bu]TiMe₂. The remaining solids in R-2 werefurther extracted with Isopar E, the solution was transferred to R-3,then dried under vacuum and re-extracted with Isopar E. This solutionwas transferred to storage bottles; analysis indicated a concentrationof 0.1403 M titanium and a volume of 4.3 L (0.6032 moles[(η⁵Me₄C₅)SiMe₂-N-t-Bu]TiMe₂). This gives an overall yield of 3.2469moles of [(η⁵Me₄C₅)SiMe₂N-t-Bu]TiMe₂, or 1063 g. This is a 72% yieldoverall based on the titanium added as TiCl₃.

Catalyst Preparation Two

Part 1: Preparation of TiCl₃(DME) 1.5

The apparatus (referred to as R-1) was set-up in the hood and purgedwith nitrogen; it consisted of a 10 L glass kettle with flush mountedbottom valve, 5-neck head, polytetrafluoroethylene gasket, clamp, andstirrer components (bearing, shaft, and paddle). The necks were equippedas follows: stirrer components were put on the center neck, and theouter necks had a reflux condenser topped with gas inlet/outlet, aninlet for solvent, a thermocouple, and a stopper. Dry, deoxygenateddimethoxyethane (DME) was added to the flask (approx. 5.2 L). In thedrybox, 300 g of TiCl₃ was weighed into an equalizing powder additionfunnel; the funnel was capped, removed from the drybox, and put on thereaction kettle in place of the stopper. The TiCl₃ was added over about10 minutes with stirring. After the addition was completed, additionalDME was used to wash the rest of the TiCl₃ into the flask. This processwas then repeated with 325 g of additional TiCl₃, giving a total of 625g. The addition funnel was replaced with a stopper, and the mixtureheated to reflux. The color changed from purple to pale blue. Themixture was heated for about 5 hours, cooled to room temperature, thesolid was allowed to settle, and the supernatant was decanted from thesolid. The TiCl₃(DME) 1.5 was left in R-1 as a pale blue solid.

Part 2: Preparation of [(Me₄C₅)SiMe₂N-t-Bu][MgCl]₂

The apparatus (referred to as R-2) was set-up as described for R-1,except that flask size was 30 L. The head was equipped with seven necks;stirrer in the center neck, and the outer necks containing condensertopped with nitrogen inlet/outlet, vacuum adapter, reagent additiontube, thermocouple, and stoppers. The flask was loaded with 7 L oftoluene, 3.09 kg of 2.17 M i-PrMgCl in Et₂O, 250 mL of THF, and 1.03 kgof (Me₄C₅H)SiMe₂NH-t-Bu. The mixture was then heated, and the etherallowed to boil off into a trap cooled to −78° C. After three hours, thetemperature of the mixture had reached 80° C., at which time a whiteprecipitate formed. The temperature was then increased to 90° C. over 30minutes and held at this temperature for 2 hours. At the end of thistime, the heater was turned off, and 2 L of DME was added to the hot,stirring solution, resulting in the formation of additional precipitate.The solution was allowed to cool to room temperature, the material wasallowed to settle, and the supernatant was decanted from the solid. Anadditional wash was done by adding toluene, stirring for severalminutes, allowing the solids to settle, and decanting the toluenesolution. The [(Me₄C₅)SiMe₂N-t-Bu][MgCl]₂ was left in R-2 as anoff-white solid.

Part 3: Preparation of [(η⁵(Me₄C₅)SiMe₂N-t-Bu]Ti(η⁴-1,3-pentadiene)

The materials in R-1 and R-2 were slurried in DME (the total volumes ofthe mixtures were approx. 5 L in R-1 and 12 L in R-2). The contents ofR-1 were transferred to R-2 using a transfer tube connected to thebottom valve of the 10 L flask and one of the head openings in the 30 Lflask. The remaining material in R-1 was washed over using additionalDME. The mixture darkened quickly to a deep red/brown color. After 15minutes, 1050 mL of 1,3-pentadiene and 2.60 kg of 2.03 M n-BuMgCl in THFwere added simultaneously. The maximum temperature reached in the flaskduring this addition was 53° C. The mixture was stirred for 2 hours,then approx. 11 L of solvent was removed under vacuum. Hexane was thenadded to the flask to a total volume of 22 L. The material was allowedto settle, and the liquid layer (12 L) was decanted into another 30 Lglass kettle (R-3). An additional 15 liters of product solution wascollected by adding hexane to R-2, stirring for 50 minutes, againallowing to settle, and decanting. This material was combined with thefirst extract in R-3. The solvent in R-3 was removed under vacuum toleave a red/black solid, which was then extracted with toluene. Thismaterial was transferred into a storage cylinder. Analysis indicatedthat the solution (11.75 L) was 0.255 M in titanium; this is equal to3.0 moles of [(η⁵-Me₄C₅)SiMe₂N-t-Bu]Ti(η⁴-1,3-pentadiene) or 1095 g.This is a 74% yield based on the titanium added as TiCl₃.

Examples 1-14 and Comparative Examples C1-C4

The polymer products of Examples 1-14 and Comparative Examples C1-C4 areproduced in a solution polymerization process using a continuouslystirred reactor. Additives (e.g., antioxidants, pigments, etc.) can beincorporated into the interpolymer products either during thepelletization step or after manufacture, with a subsequent re-extrusion.Examples 1-7 and Comparative Examples C1-C2 were each stabilized with1250 ppm calcium stearate, 500 ppm Irganox™ 1076 hindered polyphenolstabilizer (available from Ciba-Geigy Corporation), and 800 ppm PEPQ(tetrakis(2,4-di-t-butylphenyl)-4,4′-biphenylene diphosphonite)(available from Clariant Corporation). Examples 8-14 and ComparativeExamples C3-C4 were each stabilized with 500 ppm Irganox™ 1076, 800 ppmPEPQ, and 100 ppm water (as a catalyst kill agent).

The ethylene and the hydrogen were combined into one stream before beingintroduced into the diluent mixture, a mixture of C₈-C₁₀ saturatedhydrocarbons, e.g., Isopar-E hydrocarbon mixture (available from ExxonChemical Company) and the comonomer. In Examples 1-11 and ComparativeExamples C1-C4 the comonomer was 1-octene; in Examples 13-14, thecomonomer was 1-butene; and Example 12 had no comonomer. The reactorfeed mixture was continuously injected into the reactor.

The metal complex and cocatalysts were combined into a single stream andwere also continuously injected into the reactor. For Examples 1-7 andComparative Examples C1-C2, the catalyst was as prepared in CatalystDescription One set forth above. For Examples 8-14 and ComparativeExamples C2-C4, the catalyst was as prepared in Catalyst Description Twoset forth above. For Examples 1-14 and Comparative Examples C1-C4, theco-catalyst was tris(pentafluorophenyl)borane, available as a 3 wt %solution in Isopar™-E mixed hydrocarbon, from Boulder Scientific.Aluminum was provided in the form of a solution of modifiedmethylalumoxane (MMAO Type 3A) in heptane, which is available at a 2 wt% aluminum concentration from Akzo Nobel Chemical Inc.

Sufficient residence time was allowed for the metal complex andcocatalyst to react prior to introduction into the polymerizationreactor. For the polymerization reactions of Examples 1-14 andComparative Examples C1-C4, the reactor pressure was held constant atabout 475 psig. Ethylene content of the reactor, in each of Examples1-14 and Comparative Examples C1-C4, after reaching steady state, wasmaintained at the conditions specified in Table One.

After polymerization, the reactor exit stream is introduced into aseparator where the molten polymer is separated from the unreactedcomonomer(s), unreacted ethylene, unreacted hydrogen, and diluentmixture stream. The molten polymer is subsequently strand chopped orpelletized, and, after being cooled in a water bath or pelletizer, thesolid pellets are collected. Table I describes the polymerizationconditions and the resultant polymer properties.

TABLE ONE C1 Ex. 1 C2 Ex. 2 Ex. 3 Ex. 4 Ethylene feed (lb/hr)    2.0  2.0    2.0    2.0   2.0    2.0 Comonomer:olefin ratio (mole %)   18.00  18.10    12.40    12.50   12.50    8.50 Hydrogen:ethylene ratio (mole%)    0.00   1.22    0.26    0.48   1.26    0.66 Diluent:ethylene ratio(weight basis)   10.20   9.80    10.60    11.10   11.10    9.30 Catalystmetal concentration (ppm)    4   4    4    4   4    2 Catalyst flow rate(lb/hr)    0.280   0.313    0.272    0.316   0.428    0.386 Co-catalystconcentration (ppm)   88   88    88    88   88    44 Co-catalyst flowrate (lb/hr)    0.408   0.455    0.396    0.460   0.624    0.561Aluminum concentration (ppm)   10   10    10    10   10    5 Aluminumflow rate (lb/hr)    0.385   0.431    0.375    0.438   0.590    0.528Reactor temperature (° C.)   110  110   110   110  110   110 Ethyleneconcentration in reactor exit stream (weight %)    2.17   2.48    1.80   1.69   1.65    2.99 Polymer density (g/cm³)    0.858   0.855    0.875   0.871   0.870    0.897 Polymer melt viscosity at 350° F. (centipoise)309000*  350  39000*   4200  355   5200 Polymer melt index (I₂ at 190°C.)   32 16200*   246   1800* 16000*   1500* Polymer Mw  60,400  8,70030,100 16,500  7,900 15,600 Polymer Mn  29,100  4,600 17,100  9,100 4,300  8,700 Polymer Mw/Mn    2.08   1.89    1.76    1.81   1.84   1.79 Peak crystallization temperature by DSC (° C.)   23.73   27.13   55.73    55.44   59.05    78.57 Peak melting temperature by DSC (°C.)   45.63   57    68    67   67    91.04 Total percent crystallinityby DSC    7.46   9.98    18.94    17.78   19.55    36.3 FIG.   2(b)   3(b)    3(c)   3(d)    4 Ex. 5 Ex. 6 Ex. 7 C3 Ex. 8 C4 Ethylene feed(lb/hr)    3.0    3.0   3.0    3.0    3.0    3.0 Comonomer:olefin ratio(mole %)    4.40    0.40   0.40    11.80    9.10    7.40Hydrogen:ethylene ratio (mole %)    0.68    0.72   1.60    0.34    0.54   0.42 Diluent:ethylene ratio (weight basis)    5.90    5.90   5.90   9.99    9.99    8.59 Catalyst metal concentration (ppm)    5    5   5   3    3    3 Catalyst flow rate (lb/hr)    0.417    0.441   0.626   0.449    0.450    0.466 Co-catalyst concentration (ppm)   353   353 353    88    88    88 Co-catalyst flow rate (lb/hr)    0.190    0.200  0.284    0.490    0.490    0.500 Aluminum concentration (ppm)    20   20   20    9.8    9.8    9.8 Aluminum flow rate (lb/hr)    0.357   0.376   0.534    0.461    0.468    0.480 Reactor temperature (° C.)  140   140  140   110   110   120 Ethylene concentration in reactorexit stream (weight %)    4.44    4.14   4.41    1.75    1.71    1.41Polymer density (g/cm³)    0.929    0.963   0.968    0.872    0.883   0.898 Polymer melt viscosity at 350° F. (centipoise)   5600   5200 395 15,000   5000 15,000 Polymer melt index (I₂ at 190° C.)   1400*  1500* 14500*   583* Polymer melt index (I₂ at 190° C. (g/10 min.))  1500*   580* Polymer Mw 15,800 15,800  7,300 23,200 16,200 20,300Polymer Mn  8,900  8,000  3,700 11,900  8,200 10,400 Polymer Mw/Mn   1.78    1.98   1.97    1.95    1.98    1.95 Peak crystallizationtemperature by DSC (° C.)   102.76   116.01  114.76    55.73    69.27   79.85 Peak melting temperature by DSC (° C.)   112.22   129.23  127.6   68    81.97    92.62 Total percent crystallinity by DSC    38.42   76.03   79.62    18.94    28.18    36.76 FIG.    6    7(b) Ex. 9 Ex.10 Ex. 11 Ex. 12 Ex. 13 Ex. 14 Ethylene feed (lb/hr)    3.0    3.0   3.0   3.0    3.0    3.0 Comonomer:olefin ratio (mole %)    7.40    7.30  1.24    0.00    17.10    12.70 Hydrogen:ethylene ratio (mole %)   0.56    0.76   2.14    2.14    0.54    0.62 Diluent:ethylene ratio(weight basis)    8.59    8.59   7.69    7.70    9.99    9.00 Catalystmetal concentration (ppm)    3    3   32    32    8    8 Catalyst flowrate (lb/hr)    0.555    0.713   0.304    0.294    0.392    0.207Co-catalyst concentration (ppm)    88    88  1430   1430   353   353Co-catalyst flow rate (lb/hr)    0.605    0.777   0.219    0.211   0.278    0.150 Aluminum concentration (ppm)    9.8    9.8  120.0  120.0    39.8    39.8 Aluminum flow rate (lb/hr)    0.574    0.731  0.323    0.311    0.260    0.141 Reactor temperature (° C.)   110  110  110   110   110   110 Ethylene concentration in reactor exitstream (weight %)    2.17    2.48   1.80    1.69    1.65    2.99 Polymerdensity (g/cm³)    0.897    0.894   0.948    0.960    0.868    0.887Polymer melt viscosity at 350° F. (centipoise)   5200   2500  350   512  5290   5000 Polymer melt index (I₂ at 190° C. (g/10 min.))   1500*  2900* 16000*  11600* Polymer Mw 16,100 12,000  6,900  7,400 Polymer Mn 8,900  5,800  3,200  3,200 Polymer Mw/Mn    1.81    2.07   2.16    2.31Peak crystallization temperature by DSC (° C.)    78.57    81.22  109.88  116.39    47.15    65.65 Peak melting temperature by DSC (° C.)   91.04    92.43  120.5   131.11    55    78.06 Total percentcrystallinity by DSC    36.3    37.81   72.81    72.84    13.06    26.39FIG.    8    9 *Calculated on the basis of melt viscosity correlationsin accordance with the formula: I₂ = 3.6126(10^(log(η)−6.6928)/−1.1363))− 9.3185, where η = melt viscosity at 350° F.

Examples 15-16 and Comparative Example C5

The polymer products of Examples 15-16 and Comparative Example C5 wereproduced in a solution polymerization process using a well-mixedrecirculating loop reactor. Each polymer was stabilized with 2000 ppmIRGANOX™ 1076 hindered polyphenol stabilizer (available from Ciba-GeigyCorporation) and 35 ppm deionized water (as a catalyst kill agent).

The ethylene and the hydrogen (as well as any ethylene and hydrogenwhich were recycled from the separator, were combined into one streambefore being introduced into the diluent mixture, a mixture of C₈-C₁₀saturated hydrocarbons, e.g., ISOPAR™-E (available from Exxon ChemicalCompany) and the comonomer 1-octene.

The metal complex and cocatalysts were combined into a single stream andwere also continuously injected into the reactor. The catalyst was asprepared in Catalyst Description Two set forth above; the primarycocatalyst was tri(pentafluorophenyl)borane, available from BoulderScientific as a 3 wt % solution in ISOPAR-E mixed hydrocarbon; and thesecondary cocatalyst was modified methylalumoxane (MMAO Type 3A),available from Akzo Nobel Chemical Inc. as a solution in heptane having2 wt % aluminum.

Sufficient residence time was allowed for the metal complex andcocatalyst to react prior to introduction into the polymerizationreactor. The reactor pressure was held constant at about 475 psig.

After polymerization, the reactor exit stream was introduced into aseparator where the molten polymer was separated from the unreactedcomonomer(s), unreacted ethylene, unreacted hydrogen, and diluentmixture stream, which was in turn recycled for combination with freshcomonomer, ethylene, hydrogen, and diluent, for introduction into thereactor. The molten polymer was subsequently strand chopped orpelletized, and, after being cooled in a water bath or pelletizer, thesolid pellets were collected. Table Two describes the polymerizationconditions and the resultant polymer properties.

TABLE TWO  C5 Ex. 15 Ex. 16 Ethylene fresh feed rate   140   140   140(lbs/hr) Total ethylene feed rate   146.2   146.17   146.5 (lbs/hr)Fresh octene feed rate (lbs/hr)    45.4   49.5    12.67 Total octenefeed rate (lbs/hr)  Not   112    32.9 determined Total octeneconcentration  Not   11.4    3.36 (weight %) determined Fresh hydrogenfeed rate   4025  5350  16100 (standard cm³/min) Solvent and octene feedrate   840   839.4   840 (lbs/hr) Ethylene conversion rate    90.7  90.3    88.26 (wt %) Reactor temperature (° C.)   109.86   119.8  134.3 Feed temperature (° C.)    15   15    15.3 Catalystconcentration (ppm)    70   70    70 Catalyst flow rate (lbs/hr)   0.725    1.265    4.6 Primary cocatalyst   1200  2031   1998concentration (ppm) Primary cocatalyst flow    2.96    1.635    5.86rate (lbs/hr) Primary cocatalyst to    2.96    3.48    2.897 catalystmolar ratio (B:Ti) Secondary cocatalyst   198   198   198 concentration(ppm) Secondary cocatalyst    0.718    1.258    3.7 flow rate (lbs/hr)Secondary cocatalyst to    5    4.986    4.037 catalyst molar ratio(Al:Ti) Product density (g/cm³)    0.8926    0.8925    0.9369 Productmelt viscosity at 12,500 4,000   400 350° F. (centipoise) Polymer meltindex   686* 1,900* 14,000 (I₂ at 190° C.)* Polymer Mn 12,300* 8,900* 4,700* *Calculated on the basis of melt viscosity correlations inaccordance with the formulas: I₂ = 3.6126(10^(log(η)−6.6928)/−1.1363)) −9.3185, Mn = 10^([(logη+10.46)/3.56)]) where η = melt viscosity at 350°F.

Except as noted, Examples 17-19 were prepared in accordance with theprocedure set forth above with respect to Examples 1-14. In particular,Examples 17 and 18 were prepared using a catalyst prepared in accordancewith Catalyst Procedure 2. The additives employed were 1000 ppm Irganox™1076 hindered polyphenol stabilizer (available from Ciba-GeigyCorporation) and 100 ppm water. In the case of Example 18, ethylbenzene,rather than Isopar™ E mixed hydrocarbon, was utilized as the solvent.

Example 19 was prepared using a catalyst prepared in accordance withCatalyst Procedure 1. The additives employed were 1250 ppm calciumstearate, 500 ppm Irganox™ 1076 hindered polyphenol stabilizer(available from Ciba-Geigy Corporation), and 800 ppm PEPQ(tetrakis(2,4-di-t-butylphenyl)-4,4′-biphenylene diphosphonite)(available from Clariant Corporation).

The run conditions employed and a description of the resultant polymersis set forth in the following Table:

 Ex. 17  Ex. 18 Ex. 19 Ethylene fresh feed rate    2.5    3.5   3.02(lbs/hr) Total ethylene feed rate    2.5    3.5   3.02 (lbs/hr) Freshoctene feed rate    1.9    1.52   1.1 (lbs/hr) Total octene feed rate   1.9    1.52   1.1 (lbs/hr) Total octene concentration    11.44   6.47   5.52 (weight %) Fresh hydrogen feed rate   199.9   292.4 124.9 (standard cm³/min) Solvent and octene feed   14.1    20.04  16.9rate (lbs/hr) Ethylene conversion rate    75.2    85.5  69.3 (wt %)Reactor temperature (° C.)   119.8   136.3  140.4 Feed temperature (°C.)    26.9    33.93  40 Catalyst concentration    12    2.4   5 (ppm)Catalyst flow rate (lbs/hr)     .4543     .60717   .4174 Primarycocatalyst    92    92  393 concentration (ppm) Primary cocatalyst flow    .67     .3664   .18967 rate (lbs/hr) Primary cocatalyst to   —   2.16   3.3 catalyst molar ratio (B:Ti) Secondary cocatalyst   —   21.74  19.78 concentration (ppm) Secondary cocatalyst   —    0.302  0.3569 flow rate (lbs/hr) Secondary cocatalyst to    8   6 catalystmolar ratio (Al:Ti) Product density (g/cm³)    0.890    0.930   0.920Product melt viscosity at   350   400 5620 350° F. (centipoise) Polymermelt index 16,000 14,000 1400 (I₂ at 190° C.)* Polymer Mn*   4500   47009800 *Calculated on the basis of melt viscosity correlations inaccordance with the formulas: I₂ = 3.6126(10^(log(η)−6.6928)/−1.1363)) −9.3185, Mn = 10^([(logη+10.46)/3.56)]) where η = melt viscosity at 350°F.

Comparative Examples

To a 4 liter autoclave stirred reactor, 865.9 g of ISOPAR™-E hydrocarbon(available from Exxon Chemical Company) and 800.4 g 1-octene werecharged. The reactor was heated to 120° C. and hydrogen was added from a75 cc cylinder. Hydrogen was added to cause a 250 psig pressure drop inthe cylinder. The reactor was then pressurized to 450 psig of ethylene.Catalyst was added at the rate of 1 cc/min. The catalyst was as preparedin the Catalyst One Preparation set forth above and was mixed with otherco-catalysts at a ratio of 1.5 mL of a 0.005 M of Catalyst PreparationOne, 1.5 mL of a 0.015 M solution of tris(pentafluorophenyl)borane inISOPAR-E hydrocarbon mixture (a 3 wt % solution oftris(pentafluorophenyl)borane in ISOPAR-E hydrocarbon mixture isavailable from Boulder Scientific), 1.5 mL of a 0.05 M solution ofmodified methylalumoxane in ISOPAR-E hydrocarbon mixture (MMAO Type 3A)(a solution of MMAO Type 3A in heptane with a 2 wt % aluminum content isavailable from Akzo Nobel Chemical Inc.), and 19.5 mL of ISOPAR-Ehydrocarbon mixture. Ethylene was supplied on demand. The reactortemperature and pressure were set at 120° C. and 450 psig, respectively.The reaction continued for 23.1 minutes. At this time, the agitation wasstopped and the reactor contents transferred to a glass collectionkettle. The reactor product was dried in a vacuum oven overnight.

The ethylene/octene product thus prepared had a density of 0.867 g/cm³,and an I₂ at 190° C. of 842 g/10 min.

The following additional comparative examples representethylene/1-octene substantially linear polymers prepared in accordancewith the teachings of U.S. Pat. Nos. 5,272,236 and 5,278,272, thedisclosures of which are incorporated herein by reference. A descriptionof the comparative examples, as well as some representative properties,is set forth in Table Three.

TABLE THREE Melt Peak crys- Peak Total index at tallization meltingpercent 190° C. temperature temperature crystal- Density (g/10 by DSC byDSC linity (g/cm³) min.) (° C.) (° C.) by DSC Comparative 0.863 0.532.98 50.07 12.3 Ex. A Comparative 0.863 14 39.84 57.41 13.95 Ex. BComparative 0.868 0.5 42.73 56.3 15.65 Ex. C Comparative 0.87 1.0 47.2455.34 13.5 Ex. D Comparative 0.87 5 45.6 63.44 17.05 Ex. E Comparative0.87 30 49.13 60.72 18.62 Ex. F Comparative 0.885 1 62.29 80.11 26.57Ex. G Comparative 0.885 30 66.63 84.43 28.15 Ex. H Comparative 0.902 3082.47 98.78 40.41 Ex. I Comparative 0.902 4.3 80.84 99.04 39.14 Ex. JComparative 0.903 1 82.97 99.49 36.23 Ex. K Comparative 0.915 1 95.78109.0 47.91 Ex. L

Transmission Electron Micrograph Preparation and Digital AnalysisThereof

Transmission electron micrographs are taken of the specific polymers ofthe Examples and Comparative Examples, and are set forth in the FIGURESabove. In each case, the polymers were formed into compression moldedplaques having a thickness of 125 mils and a diameter of 1 inch. Theplaques were cooled at the rate of 15° C./minute. The crystallinestructure was revealed by preferential oxidation of the amorphouspolyethylene by ruthenium tetraoxide. The polymer films were exposed for120 minutes to ruthenium tetraoxide vapors generated from a solution of0.2 g ruthenium chloride and 10 mL of a 5.35 weight percent solution ofsodium hypochlorite in 100 mL of water. Sections of the plaque having athickness of 1000 angstroms were cut at room temperature with a ReichertJung Ultracut E microtome and placed on a 200 copper mesh grid having apolyvinyl Formvar support (the support is available from ElectronMicroscopy Sciences). Microscopy was done on a JEOL 2000FX TEM operatedat an accelerating voltage of 100 kilovolts. The resultant micrographsare set forth in the FIGURES, with 1 mm representing 0.01111 micrometer.

Digital images of certain of the transmission electron micrographs wereacquired using a Quantimet 570 digital image analyzer (available fromLeica, Inc.), through a CCD video camera. White top hat filters wereapplied to the optical micrographs before detection of the binaries,i.e., the lamella showed white against a grey background. The filterswere disks about 6 nanometers in size. Detection thresholds were set byvisually comparing resulting binaries with the original images. Minimalediting of the binaries was done to correct obvious omissions orinclusions encountered in the detection process.

The lengths of the depicted lamella were measured. The lamella in eachof the following ranges of length were counted: less than 40 nanometers,40-60 nanometers, 60-80 nanometers, 80-100 nanometers, 100-120nanometers, 120-140 nanometers, 140-160 nanometers, 160-180 nanometers,180-200 nanometers, and greater than 200 nanometers. The averagelamellar length was determined. As all lamella in the section were infocus, i.e., there were no lamella hidden by other lamella, the numberof lamella per cubic micron was determined by multiplying the number oflamella per square micron by the section thickness, i.e., 1000angstroms.

We claim:
 1. A non-pourable homogeneous ultra-low molecular weightethylene polymer wherein the ethylene polymer has a number averagemolecular weight (M_(n)) as determined by gel permeation chromatography,of no more than 11,000, a molecular weight distribution, Mw/Mn, asdetermined by gel permeation chromatography, of from 1.5 to 2.5, a pourpoint of greater than −30° C. as determined by ASTM Method No. D97, anda density of from 0.890 to 0.949 g/cm³.
 2. A non-pourable homogeneousultra-low molecular weight ethylene polymer wherein the ethylene polymerhas a number average molecular weight (M_(n)) as determined by gelpermeation chromatography, of no more than 11,000, a molecular weightdistribution, Mw/Mn, as determined by gel permeation chromatography, offrom 1.5 to 2.5, a pour point of greater than −30° C. as determined byASTM Method No. D97, and a density of from 0.890 to 0.899 g/cm³.
 3. Anon-pourable homogeneous ultra-low molecular weight ethylene polymerwherein the ethylene polymer has a number average molecular weight(M_(n)) as determined by gel permeation chromatography, of no more than11,000, a molecular weight distribution, M_(w)/M_(n), as determined bygel permeation chromatography, of from 1.5 to 2.5, a pour point ofgreater than −30° C., as determined by ASTM Method No. D97, wherein thepolymer has a density of from 0.900 to 0.919 g/cm³.
 4. A non-pourablehomogeneous ultra-low molecular weight ethylene polymer wherein theethylene polymer has a number average molecular weight (M_(n)) asdetermined by gel permeation chromatography, of no more than 11,000, amolecular weight distribution, M_(w)/M_(n), as determined by gelpermeation chromatography, of from 1.5 to 2.5, a pour point of greaterthan −30° C., as determined by ASTM Method No. D97, wherein the polymerhas a density of from 0.920 to 0.949 g/cm³.
 5. A non-pourablehomogeneous ultra-low molecular weight ethylene polymer wherein theethylene polymer has a number average molecular weight (M_(n)) asdetermined by gel permeation chromatography, of no more than 11,000, amolecular weight distribution, M_(w)/M_(n), as determined by gelpermeation chromatography, of from 1.5 to 2.5, a pour point of greaterthan −30° C., as determined by ASTM Method No. D97, wherein the polymerhas a density of greater than 0.950 g/cm³.
 6. A non-pourable homogenousultra-low molecular weight ethylene polymer having a density of at least0.920 g/cm³, wherein the ethylene polymer lacks spherulites and haslamella with an average length greater than 100 nanometers when viewedusing transmission electron microscopy.
 7. A non-pourable homogeneousultra-low molecular weight ethylene polymer which is characterized ashaving a number average molecular weight (M_(n)) as determined by gelpermeation chromatography, of no more than 11,000, a molecular weightdistribution, M_(w)/M_(n), as determined by gel permeationchromatography, of from 1.5 to 2.5, a pour point of at least −30° C., asdetermined by ASTM Method No. D97, wherein the ultra-low molecularweight ethylene polymer is prepared using a constrained geometrycatalyst.
 8. A non-pourable homogenous ultra-low molecular weightethylene polymer wherein the ethylene polymer has a number averagemolecular weight (M_(n)) as determined by gel permeation chromatography,of no more than 11,000, a molecular weight distribution, Mw/Mn, asdetermined by gel permeation chromatography, of from 1.5 to 2.5, a pourpoint of at least −30° C, as determined by ASTM Method No. D97, whereinthe ultra-low molecular weight ethylene polymer is prepared using aconstrained geometry catalyst.
 9. The ultra-low molecular weightethylene polymer of claim 1, wherein said comonomer is an ethylenicallyunsaturated monomer selected from the group consisting of the C₃-C₂₀α-olefins, styrene, alkyl-substituted styrene, vinylbenzocyclobutane,1,4-hexadiene, and naphthenics.
 10. The ultra-low molecular weightethylene polymer of claim 9, wherein the comonomer is selected from thegroup consisting of 1-propene, isobutylene, 1-butene, 1-hexene,1-heptene, 4-methyl-1-pentene, and 1-octene.
 11. The ultra-low molecularweight ethylene polymer of claim 9, wherein the comonomer is selectedfrom the group consisting of 1-butene, 1-hexene, 4-methyl-1-pentene,1-heptene, and 1-octene.
 12. The ultra-low molecular weight ethylenepolymer of claim 1, wherein the comonomer is a C₅-C₂₀ α-olefin.
 13. theultra-low molecular weight ethylene polymer of claim 1, wherein thecomonomer is a C₆-C₂₀ α-olefin.
 14. An ethylene polymer, comprising: anumber average molecular weight (M_(n)) less than about 11,000 asdetermined by gel permeation chromatography; a molecular weightdistribution (M_(w)/M_(n)) between about 1.5 and about 2.5 as determinedby gel permeation chromatography; a pour point greater than about −30°C. as determined by ASTM Method No. D97; a density between about 0.85g/cm³ and about 0.97 g/cm³; and a polymer backbone that is substitutedwith long chain branching such that there are between about 0.01 andabout 3 long chain branches per 1000 carbon atoms.
 15. The polymer ofclaim 14, wherein the pour point is greater than about 25° C. asdetermined by ASTM Method No. D97.
 16. The polymer of claim 14, whereinthe pour point is greater than about 50° C. as determined by ASTM MethodNo. D97.
 17. The polymer of claim 14, further comprising a peak meltingtemperature as determined by DSC that is between about 112° C. and about120° C.
 18. The polymer of claim 14, wherein the density is betweenabout 0.93 g/cm³ and about 0.95 g/cm³, and further comprising a peakmelting temperature as determined by DSC that is between about 112° C.and about 120° C.
 19. The polymer of claim 14, wherein the density isgreater than about 0.92 g/cm³.
 20. The polymer of claim 14, furthercomprising a melt index (I₂) at 190° C. of greater than about
 1300. 21.The polymer of claim 14, wherein the molecular weight distribution(M_(w)/M_(n)) is less than about 2.0 as determined by gel permeationchromatography.
 22. The polymer of claim 14, wherein the molecularweight distribution (M_(w)/M_(n)) is between 1.79 and 1.98 as determinedby gel permeation chromatography.
 23. The ethylene polymer of claim 14wherein the polymer backbone contains between about 0.03 and about 1long chain branches per 1000 carbon atoms.
 24. The ethylene polymer ofclaim 14, further comprising a composition distribution branch index(CDBI) greater than about 30 percent.
 25. The ethylene polymer of claim14, further comprising a composition distribution branch index (CDBI)greater than about 50 percent.
 26. The polymer of claim 14, furthercomprising more than 9 lamella per cubic micron that have a lengthgreater than about 100 nanometers.
 27. An ethylene polymer, comprising:a number average molecular weight (M_(n)) less than about 11,000 asdetermined by gel permeation chromatography; a molecular weightdistribution (M_(w)/M_(n)) less than about 2.5 as determined by gelpermeation chromatography; a pour point greater than about −30° C. asdetermined by ASTM Method No. D97; a density between about 0.85 g/cm³and about 0.97 g/cm³; and a composition distribution branch index (CDBI)greater than about 30 percent.
 28. The polymer of claim 27, wherein thecomposition distribution branch index (CDBI) is greater than about 50percent.
 29. The ultra-low molecular weight ethylene polymer of claim 9,wherein the comonomer is 1-hexene.
 30. The ultra-low molecular weightethylene polymer of claim 9, wherein the comonomer is 1-octene.